Image forming apparatus

ABSTRACT

In a normal print mode in which the image of an original document D is printed on a copying paper with the image of the original document not reversed, the direction of sub-scanning executed by the read means is set to a normal direction (regular direction X). In a mirror image print mode in which the image of an original document D set on a document table 2 is printed on a copying paper with the image of the original document reversed, the direction of the sub-scanning executed by the read means is switched to a direction (reverse direction X′) opposite to the normal direction.

BACKGROUND OF THE INVENTION

[0001] In an image forming apparatus such as a copying machine or thelike, an exposure means is reciprocally moved along a document table byoperation of a scanning motor, and the document table is subjected toexposure and scanning thereby to read an image on an original document,while it reciprocally moves. The image thus read is formed on a copyingpaper as an image forming medium. A pulse motor is used as the scanningmotor.

[0002] The exposure means comprises, as its components, a carriage wherean exposure lamp and a carriage on which the exposure lamp is mounted.The carriage is provided to be reciprocally movable along the documenttable, and is connected to the shaft of the scanning motor through amotion transmission mechanism such as a belt, wire, or the like. Thecarriage receives the motion force from the scanning motor andreciprocally moves.

[0003] An image forming apparatuses of this kind has a function of amirror image print mode in which the image of an original document isprinted as a mirror image which is reversed from the image of theoriginal document. In printing of this mirror image print mode, an imageread from an original document is reversed with use of a memory, and thereversed image which is a mirror image is printed on a copying paper.

[0004] That is, a memory for reversing the image and an image processingfunction for reversing the image are required to carry out printing inthe mirror image print mode. An image forming apparatus of a low cost,which cannot equipped with the memory and image processing function,cannot carry out printing in the mirror image print mode.

BRIEF SUMMARY OF THE INVENTION

[0005] The present invention has an object of providing an image formingapparatus and method of controlling the apparatus which are capable ofprinting an image of an original document as a reversed image thereof,i.e., a so-called mirror image, without requiring costs.

[0006] An image forming apparatus according to the present inventioncomprises: a document table on which an original document is set; readmeans for reading an image of the original document set on the documenttable, by optical main scanning on the original document set on theoriginal table, in one direction, and sub-scanning in which the mainsscanning is shifted in a direction perpendicular to the one direction; aprinter section for executing main scanning and sub-scanning insynchronization with the main scanning and the sub-scanning performed bythe read means, thereby to print the image read by the read means, ontoan image forming medium; and control means for setting the direction ofthe sub-scanning of the read means to a normal direction, in case of anormal print mode in which the image of the original document set on thedocument table is printed on the image forming medium, with the imagenot reversed, and for setting the direction of the sub-scanning to adirection opposite to the normal direction, in case of a mirror imageprint mode in which the image of the original document set on theoriginal table is printed on the image forming medium, with the imagereversed.

[0007] Additional objects and advantages of the invention will be setforth in the description which follows, and in part will be obvious fromthe description, or may be learned by practice of the invention. Theobjects and advantages of the invention may be realized and obtained bymeans of the instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0008] The accompanying drawings, which are incorporated in andconstitute a part of the specification, illustrate presently preferredembodiments of the invention, and together with the general descriptiongiven above and the detailed description of the preferred embodimentsgiven below, serve to explain the principles of the invention.

[0009]FIG. 1 is a view showing an outer appearance of the firstembodiment;

[0010]FIG. 2 is a view showing the internal structure of the firstembodiment;

[0011]FIG. 3 is a view showing the structure of a document table and itsperiphery in the first embodiment;

[0012]FIG. 4 is a view showing the structure of an exposure lamp and itsperiphery in the first embodiment;

[0013]FIG. 5 is a block diagram of a control circuit in the firstembodiment;

[0014]FIG. 6 is a block diagram showing a main part of FIG. 5;

[0015]FIG. 7 is a view showing selection conditions of a magneticexcitation system of the scanning motor in the first embodiment;

[0016]FIG. 8 is a view showing patterns of various signals with respectto the scanning motor in the first embodiment;

[0017]FIG. 9A and FIG. 9B are flowcharts for explaining functions of thedocument table read systems in the first and second embodiments;

[0018]FIG. 10 is a view showing an example of an original document usedin the first and second embodiments;

[0019]FIG. 11 is a view showing a state of the original document shownin FIG. 10, which is set on the document table, and main scanning andsub-scanning for reading an image in a normal print mode;

[0020]FIG. 12 is a view showing a state in which an image read in FIG.11 is printed on a copying paper by a laser beam and a photosensitivedrum;

[0021]FIG. 13 is a view showing a state in which the image read in FIG.11 is printed on a copying paper, and main scanning and sub-scanning ofthe printing;

[0022]FIG. 14 is a view showing a state in which the original documentshown in FIG. 10 is set on the document table, and main scanning andsub-scanning on the original document in image reading in a mirror imageprint mode;

[0023]FIG. 15 is a view showing a state in which the image read in FIG.14 is printed onto a copying paper by a laser beam and a photosensitivedrum;

[0024]FIG. 16 is a view showing a state in which the image read in FIG.14 is printed onto a copying paper and main scanning and sub-scanning ofthe printing;

[0025]FIG. 17 is a view showing an outer appearance of the secondembodiment;

[0026]FIG. 18 is a view showing the internal structure of the secondembodiment;

[0027]FIG. 19 is a view showing the structure of the document table andits periphery in the second embodiment;

[0028]FIG. 20 is a view showing the structure of an exposure lamp andits periphery in the second embodiment;

[0029]FIG. 21 is a block diagram of a control circuit in the secondembodiment;

[0030]FIG. 22 is a flowchart for explaining functions of the sheetthrough system in the second embodiment;

[0031]FIG. 23 is a view showing a state in which the original documentshown in FIG. 10 is set on the automatic document feeder;

[0032]FIG. 24 is a view showing a state in which the original documentshown in FIG. 23 is fed to the document read window and passes over thedocument read window, and main scanning and sub-scanning for readingimage from the original document;

[0033]FIG. 25 is a view showing the image read in FIG. 24 is printed ona copying paper by a laser beam and a photosensitive drum in case of amirror image print mode;

[0034]FIG. 26 is a view showing a state in which an image is printed ona copying paper shown in FIG. 25, and main scanning and sub-scanning ofthe printing;

[0035]FIG. 27 is a view showing a state in which the image read in FIG.24 is written into a page memory in case of a normal print mode;

[0036]FIG. 28 is a view showing a state in which an image is read fromthe memory shown in FIG. 27;

[0037]FIG. 29 is a view showing a state in which the image read in FIG.28 is printed on a copying paper by a laser beam and a photosensitivedrum; and

[0038]FIG. 30 is a view showing a state in which an image is printed onthe copying paper shown in FIG. 29, and main scanning and sub-scanningof the printing.

DETAILED DESCRIPTION OF THE INVENTION

[0039] [1] In the following, the first embodiment of the presentinvention will be explained with reference to the drawings.

[0040] As shown in FIG. 1 and FIG. 2, a transparent document table(glass plate) 2 for setting an original document is provided at an upperpart of the body 1, and a cover 3 is provided to be freelyopenable/closable over the document table 2.

[0041] As shown in FIG. 3, an indicator part 2 a is provided at an endpart of the document table 2. A gap part between the indicator part 2 aand the document table 2 serves as a reference position 2 b. An originaldocument D is set aligned with the reference position 2 b. That is, theside of the indicator part 2 a (left side in the figure) with respect tothe reference position 2 b as a boundary is a non-document set area, andthe other side (right side in the figure) is a document set area.

[0042] A carriage 4 is provided in the lower surface side of thedocument table 2, and an exposure lamp 5 is provided on the carriage 4.An exposure means is constructed by the carriage 4 and the exposure lamp5. The carriage 4 can reciprocally move along the lower surface of thedocument table 2. The lower surface side of the indicator part 2 a andthe original document D on the document table 2 are exposed as theexposure lamp 5 is lightened while the carriage 4 reciprocally movesfrom the non-document set area to the document set area.

[0043] By this exposure, a reflection light image of the originaldocument D set on the document table 2 is obtained, and it is projectedon an image signal output means such as a CCD (Charge Coupled Device) 10by reflection mirrors 6, 7, and 8, and a magnification change lens block9. The CCD 10 has a large number of photoelectric conversion elements ina light receiving area. The light receiving area is subjected toline-scanning, and an image signal is outputted by repeating theline-scanning.

[0044] The carriage 4, exposure lamp 5, reflection mirrors 6, 7, and 8,magnification change lens block 9, and CCD 10 construct a read meanscapable of optically reading an original document D set on the documenttable 2. That is, an original document D set on the document table 2 issubjected to optical main scanning in one direction by this read means,and the main scanning is repeated as the reciprocal motion of theexposure lamp 5. Repetition of the main scanning in accordance with thereciprocal motion of the exposure lamp 5 is called sub-scanning. FIG. 19shows the directions of the main scanning and the sub-scanning as X andY, respectively.

[0045] The image signal outputted from the CCD 10 is amplified andconverted into a digital signal. The digital signal is processedappropriately by the image processing section and is thereafter suppliedto a laser unit 27. The laser unit 27 emits a laser beam B in accordancewith the input signal.

[0046] In the lower surface side of the indicator part 2 a as anon-document-set area, a black reference plate 12 and a white referenceplate 13 as color reference members for shading correction are arrangedorderly along the motion direction of the exposure lamp 5. Bothreference plates have a dimensional shape corresponding to the length ofthe indicator part 2 a in its lengthwise direction.

[0047] A plurality of document sensors 11 are provided in the lowersurface side of the document table 2. Presence or absence of an originaldocument D and the size thereof are detected optically by these sensors.

[0048] As shown in FIG. 4, the carriage 4 is movably mounted on a rail51. Further, a wire 52 is connected to the carrier 4, and the wire 52 ishung between a drive pulley 53 a and a slave pulley 53 b. The drivepulley is connected to a deceleration pulley 54, and the decelerationpulley 54 is connected to a pulley 56 of the scanning motor 57 through atiming belt 55. A pulse motor is used as the scanning motor 57. Movingposition of the carriage 4 is managed by the number of drive voltagepulses supplied to the scanning motor 57 (e.g., the number of steps).

[0049] The outer peripheral surface of the body 1 is formed by a cover58. A reference position switch 61 is provided inside this cover 58. Thereference position switch 61 has a slit for receiving insertion of alight shielding plate attached to the carriage 4, and optically detectswhether or not the light shielding plate 60 enters in the slit. If thelight shielding plate enters, the reference position switch is turnedon. Otherwise, it is turned off. When the reference position switch 61is turned on, it is determined that the carriage 4 exists at apredetermined reference position.

[0050] The scanning section is constructed by the structure describedabove from the document table 2 to the reference position switch 61.

[0051] Meanwhile, a photosensitive drum 20 is provided to be rotatableat the substantial center part in the body 1. An electrostatic charger21, a developing device 22, a transfer device 23, a separator 24, acleaner 25, and a discharger 26 are orderly provided around thephotosensitive drum 20. Further, a laser beam B emitted from the laserunit 27 described above is irradiated on the surface of thephotosensitive drum 20 through a space between the electrostatic charger21 and the developing device 22.

[0052] At a bottom part of the body 1, a plurality of paper feedcassettes 30 are provided. These cassettes 30 contain a large number ofcopying papers C of sizes which are respectively different from eachother of the cassettes. In response to an ON-operation on a print key 83described later, copying papers are taken out one after another from anyone of the paper feed cassettes 30. To take out papers, each paper feedcassette 30 is provided with a pick-up roller 31. A picked-up copyingpaper C is separated from the paper feed cassette 30 and is fed to aresist roller 33. The resist roller 33 feeds the copying paper C tobetween the photosensitive drum 20 and the transfer device 23 at timingin consideration of the rotation of the photosensitive drum 20.

[0053] The electrostatic charger 21 applies a high voltage to thephotosensitive drum 20, thereby to charge an electrostatic charge on thesurface of the photosensitive drum 20. After this electrostaticcharging, a laser beam B emitted from the laser unit 27 is irradiated onthe surface of the photosensitive drum 20. The laser unit 27 performsmain scanning (line scanning) on the surface of the photosensitive drum20 in one direction, and sub-scanning in which the main scanning isrepeated in accordance with rotation of the photosensitive drum 20,thereby to form an electrostatic latent image corresponding to an imageread by the scanner section, on the surface of the photosensitive drum20.

[0054] The electrostatic latent image on the photosensitive drum 20 isdeveloped as it receives a developing agent (toner) from the developingdevice 22. This developed image is transferred to a copying paper C bythe transfer device 23. The copying paper to which the developed imagehas been transferred is separated from the photosensitive drum 20 by theseparator 24. The developing agent and charges remain on the surface ofthe photosensitive drum 20 from which the copying paper C has beenseparated. The remaining developing agent is removed by the cleaner 25.The remaining charges are removed by the discharger 28.

[0055] The copying paper C separated from the photosensitive drum 20 isfed to a fixing device 42 by a conveyer belt 41. The fixing device 42fixes the transferred image on the copying paper C by heat. The copyingpaper C on which the image has already been fixed is fed out to a sorter44 by a feed-out roller 43. The sorter 44 includes a plurality ofcontainer parts 45 disposed vertically, and distributes a predeterminednumber of sheets of printed copying papers to each of the containerparts 45. Also, the sorter 44 comprises a staple unit 46 for staplingcopying papers contained in each container part 45 for every containerpart 45.

[0056] The printer section is thus constructed by the structureexplained above from the photosensitive drum 20 to the sorter 44, inwhich main scanning and sub-scanning are executed in synchronizationwith those of the scanner section and the image read by the scannersection is printed on a copying paper C.

[0057]FIG. 5 shows a total control circuit.

[0058] A system CPU 70, a control panel CPU 80, a scanner CPU 90, and aprinter CPU 100 are connected to each other. The system CPU 70 totallycontrols the control panel CPU 80, scanner CPU 90, and the printer CPU100.

[0059] Further, the system CPU 70 is connected with a ROM 71 for storinga control program, a RAM 72 for storing data, a NVM 73, and an imageprocessing section 74.

[0060] The control panel CPU 80 is connected with a key input section81, a liquid crystal display 82, and a print key 83. The key inputsection 81 has a power switch a document size specification key, amagnification specification key, and the like. The liquid crystaldisplay 82 displays information according to an operation on the keyinput section 81, and various information to be notified to the user.

[0061] The scanner CPU 90 is connected with a RAM 92 for storing data, ashading correction part (SHD) 93, a CCD driver 94, a scanning motordriver 95, the exposure lamp 5, each of the document sensors 11, and thelike. The CCD driver 94 drives the CCD 10. The scanning motor driver 95drives the scanning motor 57.

[0062] The printer CPU 100 is connected with a ROM 101 for storingcontrol programs, a RAM 102 for storing data, a laser driver 103, apolygon motor driver 104, a main motor driver 106, and a sorter 44. Thelaser driver 103 drives the laser unit 27. The polygon motor driver 104drives a polygon motor as a drive source of a polygon mirror forscanning the laser beam B with respect to the photosensitive drum 20.The main motor driver 106 drives a main motor 107 as a drive source forthe photosensitive drum 20, the paper feed mechanism, and the like.

[0063] The system CPU 70 and the scanner CPU 90 include the followingcontrol means (1) for their main function.

[0064] (1) Control means for setting the sub-scanning direction of theread means to a normal direction (regular direction X) in case of anormal print mode in which an image of an original document set on thedocument table 2 is printed on a copying paper C without reversing theimage, and for switching the sub-scanning direction of the read means toan opposite direction (an opposite direction X′) which is opposite tothe normal direction in case of a mirror-image print mode in which animage of an original document D set on the document table 2 is printedin a reversed condition, as a so-called mirror image, on a copying paperC.

[0065] Meanwhile, as shown in FIG. 6, a gate array 96 and a D/Aconverter 97 are provided between the scanner CPU 90 and the scanningmotor driver 95.

[0066] The gate array 96 outputs a control signal H.OFF-1 for specifyingmagnetic excitation ON and OFF of the scanning motor 57, a controlsignal CWCCW for specifying regular rotation and reversal rotation ofthe scanning motor 57, and data signals DATA0, DATA1, DATA2, and DATA3for specifying magnetic excitation systems of the scanning motor 57.These signals are supplied to the scanning motor driver 95. The D/Aconverter 97 converts current value specification data, which isgenerated from the scanner CPU 90, into a voltage signal SCNVREFA forspecifying a relative current value with respect to the scanning motor57. This voltage signal SCNVREFA is supplied to the scanning motordriver 95.

[0067] Also, a reference clock signal SCCLK-0 is supplied from thescanner CPU 90 to the scanning motor driver 95. The scanning motordriver 95 outputs a drive voltage pulse synchronized with a rise of thereference clock signal SCCLK-0. This drive voltage pulse is supplied tothe scanning motor 57. The scanner CPU 90 changes the interval of thereference clock signal SCCLK-0 in accordance with the magnification setby the key input part 81. In accordance with the change, the interval ofthe drive voltage pulse supplied to the scanning motor 57 is changed sothat the rotation speed of the scanning motor 57, i.e., the motion speedof the carriage 4 changes.

[0068]FIG. 7 shows selection conditions as to which magnetic excitationsystem should be selected in correspondence with the 4-bit data signalsDATA0, DATA1, DATA2, and DATA3 in case where a five-phase pulse motor isused as the scanning motor 57. In the present embodiment, any of themagnetic excitation systems A, B, C, and D is selected.

[0069]FIG. 8 shows an example of patterns of signals concerning thedriving of the scanning motor 57. In this example, the magneticexcitation system C is selected.

[0070] When the carriage 4 moves forward, the scanning motor 57 firstlyaccelerates toward an aimed speed, then operates at an equal speed afterthe aimed speed is reached, and finally decelerates. While the scanningmotor is driving at an equal speed, the image on an original document Dis read. When the carriage moves back, the scanning motor 57 firstlyoperates to accelerate, then operates at an equal speed, and finallydecelerates. Switching between the acceleration, operation at an equalspeed, and deceleration is realized by changing the interval of thereference clock signal SCCLK-0.

[0071] Next, functions and effects will be explained with reference tothe flowcharts shown in FIGS. 9A and 9B.

[0072] Which of “25 to 47%”, “48 to 95%”, “96 to 194%”, and “195 to400%” is the copy magnification specified by the key input section 81 isdetermined (steps 201, 202, and 203). In case where the copymagnification is “25 to 47%” (YES in the step 201), the magneticexcitation system A is selected (step 204). In case where the copymagnification is “48 to 95%” (NO in the step 201 and YES in the step202), the magnetic excitation system B is selected (step 205). In casewhere the copy magnification is “96 to 194%” (NO in the step 201, NO inthe step 202, and YES in the step 203), the magnetic excitation system Cis selected (step 206). In case where the copy magnification is “195 to400%” (NO in the step 201, NO in the step 202, and NO in the step 203),the magnetic excitation system D is selected (step 207).

[0073] As indicated by the selection conditions in FIG. 7, the rotationangle of the scanning motor 57 corresponding to one step is set to“0.72°”, according to the magnetic excitation system A. The rotationangle of the scanning motor 57 corresponding to one step is set to“0.36°”, according to the magnetic excitation system B. The rotationangle of the scanning motor 57 corresponding to one step is set to“0.288°”, according to the magnetic excitation system C. The rotationangle of the scanning motor 57 corresponding to one step is set to“0.09°”, according to the magnetic excitation system D. That is, as thelarger copy magnification increases, a greater rotation angle of thescanning motor 57 corresponding to one step is set so that the motionspeed of the carriage 4 is lowered.

[0074]FIG. 10 shows an example of an original document D on which animage such as a character “A” is written on its surface. D1 denotes theleft end, D2 denotes the right end, D3 denotes the upper end, and D4denotes the lower end. This original document D is set on the originaldocument table 2 with its surface oriented downward. This setting statusand the size of the original document D are detected by each documentsensor 11 (YES in the step 208 and step 209).

[0075] If the normal print mode for printing the image of the originaldocument D in a reversed state is specified by the key input section 81(NO in the step 210), the reference position 2 b with which the originaldocument should be aligned is set as a start end position for imagereading in the regular direction of the sub-scanning (step 211).Further, in the regular direction X of the sub-scanning, a predeterminedposition including the document size detected by each document sensor11, i.e., a position which exceeds the lateral width between D2 and D1shown in FIG. 11 is set as a finish end position of the image reading(step 212).

[0076] A scanning home position is set at a position at a predetermineddistance (necessary for acceleration of the carriage 4) from the startend position set as described above in the more proximal end side in theregular direction X of the sub-scanning (step 213). A motion targetposition of the carriage 4 is set at a position at a predetermineddistance (necessary for deceleration of the carriage 4) from the finishend position set as described above in the distal side in the regulardirection X of the sub-scanning (step 214). Note that distancesnecessary for acceleration and deceleration of the carriage 4 are setvariably in correspondence with the copy magnification.

[0077] The number of reference steps necessary to move the carriage 4from the scanning home position to the motion target position iscalculated (step 215). The number of reference steps thus calculated isconverted into an actual number of steps according to the magneticexcitation system selected as described previously (step 216). Theactual number of steps is divided for acceleration, equal-speedoperation, and deceleration (step 217).

[0078] When the print key 83 is turned on (YES in the step 218), thecarriage 4 is moved to the scanning home position, and the scanningmotor 57 is driven on the basis of the actual number of steps. By thisdriving, the carriage 4 is reciprocally moved between the scanning homeposition and the motion target position (step 219).

[0079] On the forward way of the reciprocal motion of the carriage 4(exposure lamp 5), the exposure lamp 5 is lightened so that the surfaceof the original document D is exposed from the right end D2 toward theleft end D1. Reflection light from the original document D is projectedon the CCD 10. Line scanning on the light receiving area is repeated onthe CCD 10, thereby to read an image of the original document D (step220). Repetitions of line scanning on the CCD 10 correspond respectivelyto the main scanning operations R1, R2, . . . Rn on the originaldocument D in one direction Y, as shown in FIG. 11. The main scanningoperations R1, R2, . . . Rn shift in the direction X (the regulardirection of the sub-scanning) perpendicular to the one direction Y, asthe exposure lamp 5 moves on the forward way of the reciprocal motion.

[0080] The read image is printed on a copying paper C through thephotosensitive drum 20 by scanning on the photosensitive drum 20 withthe laser beam B emitted from the laser unit 27 (step 221).

[0081] That is, the laser beam B modulated on the basis of the readimage is emitted from the laser unit 27. As shown in FIG. 12, this laserbeam B is swung in the axis direction of the photosensitive drum 20,thereby to repeat line scanning on the surface of the photosensitivedrum 20. By this repetition of line scanning and rotation of thephotosensitive drum 20, an electrostatic latent image is formed on thesurface of the photosensitive drum 20. This electrostatic latent imagecorresponds to a reversed image of the character “A” on the originaldocument D. This electrostatic latent image is developed to form avisual image which is transferred to a copying paper C. On the copyingpaper C, C1 denotes its left end, C2 denotes its right end, C3 denotesits upper end, and C4 denotes its lower end.

[0082] Repetitions of line scanning with the laser beam B correspondrespectively to main scanning operations P1, P2, . . . Pn in onedirection Y on the copying paper C, as shown in FIG. 13. These mainscanning operations P1, P2, . . . Pn shift in the direction X (which isthe regular direction of the sub-scanning) perpendicular to the onedirection Y, i.e., in the direction from the left end Cl to the rightend C2 of the copying paper C.

[0083] Thus, the image of the original document D, which is notreversed, is printed on the copying paper C. The printed copying paper Cis fed to the sorter 44. If a plurality of printed copying papers C arelayered and stapled, the staple unit 46 operates to perform stapling Sat a specific position on each copying paper C, as shown in FIG. 13. Thespecific position is a corner part existing between the right end C2 andthe lower end C4 of each copying paper C and is situated at an upperleft position where it is viewed with respect to the printed image takenas a reference.

[0084] Next, explanation will be made of a mirror image print mode inwhich the image of the original document D is printed, reversed.

[0085] An original document D is set on the document table 2 with itssurface oriented downward like in the normal mode. This setting statusand the size of the original document D are detected by each documentsensor 11 (YES in step 208 and step 209).

[0086] If a mirror print mode is specified by the key input section 81(YES in step 210), a predetermined position which includes the documentsize detected by each document sensor 11, i.e., a position exceeding thelateral width between D2 and D1 shown in FIG. 14 is set as a start endposition for image reading (step 222). Further, a reference position 2 bfor document setting is set as a finish end position of image reading inthe reverse direction X′ of the sub-scanning (step 223).

[0087] A scanning home position is set at a position at a predetermineddistance (necessary for acceleration of the carriage 4) from the startend position set as described above, in the more proximal side in thereverse direction X′ of the sub-scanning (step 224). A motion targetposition of the carriage 4 is set at a position at a predetermineddistance (necessary for deceleration of the carriage 4) from the finishend position set as described above in the distal side in the reversedirection X′ of the sub-scanning (step 225). Note that distancesnecessary for acceleration and deceleration of the carriage 4 are setvariably in correspondence with the copy magnification.

[0088] The number of reference steps necessary to move the carriage 4from the scanning home position to the motion target position iscalculated (step 215). The number of reference steps thus calculated isconverted into an actual number of steps according to the magneticexcitation system selected as described previously (step 216). Theactual number of steps is divided for acceleration, equal-speedoperation, and deceleration (step 217).

[0089] When the print key 83 is turned on (YES in the step 218), thecarriage 4 is moved to the scanning home position, and the scanningmotor 57 is driven on the basis of the actual number of steps. By thisdriving, the carriage 4 is reciprocally moved between the scanning homeposition and the motion target position (step 219).

[0090] On the forward way of the reciprocal motion of the carriage 4(exposure lamp 5), the exposure lamp 5 is lightened so that the surfaceof the original document D is exposed from the left end D1 toward theright end D2. Reflection light from the original document D is projectedon the CCD 10. Line scanning on the light receiving area is repeated onthe CCD 10, thereby to read an image of the original document D (step220). Repetitions of line scanning on the CCD 10 correspond respectivelyto the main scanning operations R1, R2, . . . Rn on the originaldocument D in one direction Y, as shown in FIG. 14. The main scanningoperations R1, R2, . . . Rn shift in the direction X′ (the reversedirection of the sub-scanning) perpendicular to the one direction Y, asthe exposure lamp 5 moves on the forward way of the reciprocal motion.

[0091] The read image is printed on a copying paper C through thephotosensitive drum 20 by scanning on the photosensitive drum 20 withthe laser beam B emitted from the laser unit 27 (step 221).

[0092] That is, the laser beam B modulated on the basis of the readimage is emitted from the laser unit 27. As shown in FIG. 15, this laserbeam B is swung in the axis direction of the photosensitive drum 20,thereby to repeat line scanning on the surface of the photosensitivedrum 20. By this repetition of line scanning and rotation of thephotosensitive drum 20, an electrostatic latent image is formed on thesurface of the photosensitive drum 20. This electrostatic latent imageis not reversal of the character “A” on the original document D butdirectly corresponds to the image of the character. This electrostaticlatent image is developed to form a visual image which is transferred toa copying paper C.

[0093] Repetitions of line scanning with the laser beam B correspondrespectively to main scanning operations P1, P2, . . . Pn in onedirection Y on the copying paper C, as shown in FIG. 16. These mainscanning operations P1, P2, . . . Pn shift in the direction X (which isthe regular direction of the sub-scanning) perpendicular to the onedirection Y, i.e., in the direction from the left end C1 to the rightend C2 of the copying paper C.

[0094] Thus, the image of the original document D is printed, as amirror image which is reversal of the original image, on the copyingpaper C. The printed copying paper C is fed to the sorter 44. If aplurality of printed copying papers C are layered and stapled, thestaple unit 46 operates to perform stapling S at a specific position oneach copying paper C, as shown in FIG. 16. Like the normal print mode,the specific position is a corner part existing between the right end C2and the lower end C4 of each copying paper C and is situated at an upperleft position where it is viewed with respect to the printed image takenas a reference.

[0095] As described above, in printing in the mirror-image print mode,the direction of sub-scanning for reading an image is switched to thereverse direction X′ which is opposite to the sub-scanning direction inthe normal print mode. In this manner, the image on the originaldocument D can be printed as a mirror image without requiring a memoryor an image processing function for reversal. That is, even an imageforming apparatus of a low-cost type which cannot be equipped with amemory or an image processing function for reversal can achieve printingin the mirror image print mode.

[0096] In addition, the position of the staple S stapling S with respectto each copying paper C can be set in common to the cases of the normalprint mode and the mirror image print mode. That is, both in the normaland mirror mode print modes, stapling S can be performed always at aproper position in relation to an image to be printed, as a reference.

[0097] [2] The second embodiment of the present invention will now beexplained with reference to the drawings. In the drawings, the sameparts as those of the first embodiment will be denoted at the samereference symbols as those of the first embodiment, and detailedexplanation thereof will be omitted herefrom.

[0098] As shown in FIGS. 17, 18, 19, and 20, an automatic documentfeeder (ADF) 47 is provided to be openable/closable on the documenttable 2. The automatic document feeder 47 has a tray 47 a where anoriginal document is set. The feeder 47 feeds a plurality of sheets ofan original document D, one after another, to a document read window 59,and lets them pass through the window. Further, each sheet of theoriginal document D which has passed there is discharged to the lowersurface side of the tray 47 a.

[0099] The document read window 59 is made of transparent glass and isprovided adjacent to the indicator part 2 a. The carriage 4 can move toa position corresponding to the document read window 59 and can stopthere. At the same time when the carriage 4 stops at that position, theautomatic document feeder 47 operates and the exposure lamp 5 islightened, so that the original document D which passes over thedocument read window 59 is exposed through the document read window 59.Reflection light from the original document D is projected onto the CCD10 by the reflection mirrors 6, 7, and 8 and the magnification changelens block 9.

[0100] The carriage 4, exposure lamp 5, reflection mirrors 6, 7, and 8,magnification change lens block 9, and CCD 10 construct a second readmeans for optically reading the original document D which passes overthe document read window 59. That is, the original document D which ispassing over the document read window 59 is subjected to opticalmain-scanning in one direction, and the main scanning is repeated as theoriginal document passes over. Repetitions of the main scanning inaccordance with passing of the original document D are calledsub-scanning. FIG. 19 shows a case where the direction of the mainscanning is Y and the direction of the sub-scanning is X.

[0101] Meanwhile, a first read means for optically reading an originaldocument D set on the document table 2 is constructed by the carriage 4,exposure lamp 5, reflection mirrors 6, 7, and 8, magnification changelens block 9, and CCD 10. That is, the original document D set on thedocument table 2 is subjected to optical main scanning in one direction,and the main scanning is repeated in accordance with the motion of theexposure lamp 5 on the forward way of its reciprocal motion. Repetitionof the main scanning according to the motion of the exposure lamp on theforward way of its reciprocal motion is taken as sub-scanning. The mainscanning direction Y and the sub-scanning direction X are the same asthose of the second read means.

[0102]FIG. 21 shows a total control circuit.

[0103] The system CPU 70 is connected with a page memory control part75, which is connected with a page memory 76.

[0104] The scanner CPU 90 is connected with the automatic documentfeeder 47. The automatic document feeder 47 comprises a document sensor47 b for detecting presence or absence and an original document D on thetray 47 a and the size thereof if any.

[0105] The system CPU 70 and the scanner CPU 90 has the followingcontrol means (11) and (12) as its main functions.

[0106] (11) A first control means for letting the first read meansfunction to set the sub-scanning direction of the first read means inthe normal direction (regular direction X) in case of the normal printmode in which the image of an original document D set on the documenttable 2 is printed on a copying paper C, not reversed, and for lettingthe first read means function to switch the sub-scanning direction ofthe first read means to the direction (reverse direction X′) opposite tothe normal direction in case of the mirror image print mode in which theimage of an original document set on the document table 2 is printed ona copying paper C, reversed as a mirror image.

[0107] (12) A second control means for letting the second read meansfunction in case of the mirror image print mode in which the image of anoriginal document set on the automatic document feeder 47 is printed ona copying paper C, reversed.

[0108] The other points of its structure are the same as those of thefirst embodiment.

[0109] The functions and effects thereof will now be explained.

[0110] With respect to printing of a document table reading system inwhich printing is carried out with an original document D is set on thedocument table 2, the functions are the same as those of the firstembodiment, and therefore, detailed explanation thereof will be omittedherefrom.

[0111] In the following, with reference to the flowchart shown in FIG.22, explanation will be made of printing according to a sheet-throughreading system in which printing is carried out with the originaldocument D set on the automatic document feeder 47.

[0112] One or a plurality of sheets of an original document D are set onthe tray 47 a of the automatic document feeder 47 with their surfacesoriented upward. This setting status and size of the original document Dare detected by the document sensor 47 b of the automatic documentfeeder 47 (YES in the step 301 and the step 302).

[0113] When the print key 83 is turned on (YES in the step 303), thecarriage 4 is moved to a position corresponding to the document readwindow 59 and one sheet of the original document D is fed to thedocument read window 59 by the automatic document feeder 47 (step 304).The fed sheet of original document D passes over the document readwindow 59 with its surface facing toward the document read window 59.The original document D which has passed over is discharged to the lowersurface side of the tray 47 a of the automatic document feeder 47.

[0114] When the original document D passes over the document read window59, the surface of the original document D is exposed by the lightenedexposure lamp 5. At this time, exposure shifts from the left end D1 ofthe original document D to the right end D2 thereof. Reflection lightfrom the original document D by this exposure is projected on the CCD10. The CCD 10 repeats line scanning on the light receiving area,thereby to read an image of the original document D (step 305).Repetitions of the line scanning by the CCD 10 respectively correspondto main scanning operations R1, R2, . . . Rn in one direction Y of theoriginal document D. These main scanning operations R1, R2, . . . Rnshift in the direction X′ (the reverse direction of the sub-scanning)perpendicular to the direction Y as the original document D passes over.

[0115] If the mirror image print mode is specified by the key input part81 (YES in step 306), the read image is printed through thephotosensitive drum 20 by the scanning on the photosensitive drum 20with the laser beam B emitted from the laser unit 27 (step 307).

[0116] That is, the laser beam B modulated on the basis of the readimage is emitted from the laser unit 27. As shown in FIG. 25, this laserbeam B is swung in the axis direction of the photosensitive drum 20,thereby to repeat line scanning on the surface of the photosensitivedrum 20. By this repetition of line scanning and rotation of thephotosensitive drum 20, an electrostatic latent image is formed on thesurface of the photosensitive drum 20. This electrostatic latent imageis not reversal of the image of the character “A” on the originaldocument D but directly corresponds to the image. This electrostaticlatent image is developed to form a visual image which is transferred toa copying paper C.

[0117] Repetitions of line scanning with the laser beam B correspondrespectively to main scanning operations P1, P2, . . . Pn in onedirection Y on the copying paper C, as shown in FIG. 26. As the copyingpaper is fed, the main scanning operations P1, P2, . . . Pn shift in thedirection X (which is the regular direction of the sub-scanning)perpendicular to the one direction Y, i.e., in the direction from theleft end C1 to the right end C2 of the copying paper C.

[0118] Thus, the image of the original document D is reversed andprinted on the copying paper C. The printed copying paper C is fed tothe sorter 44.

[0119] If there is any sheet of the original document D remaining on theautomatic document feeder 47 (NO in the step 308), the processes of thesteps 304, 305, 306, and 307 are repeated. When no sheet of the originaldocument D remains on the automatic document feeder (YES in the step308), the printing ends.

[0120] As described above, in the mirror image print mode according tothe sheet-through read system, the image of an original document D isread from the left end D1 to the right end D2, and therefore, a mirrorimage thereof can be formed on a copying paper C by directly printingthe read image without reversing it.

[0121] If a plurality of printed copying papers C are layered andstapled, the staple unit 46 operates to perform stapling S at a specificposition on each copying paper C, as shown in FIG. 26. The specificposition is a corner part existing between the right end C2 and thelower end C4 of each copying paper C and is situated at an upper leftposition where it is viewed with respect to the printed image taken as areference, like in the normal print mode and the mirror image print modeaccording to the document table read system.

[0122] Otherwise, if the normal print mode is specified by the key inputpart 81 (NO in the step 306), the read image is reversed in thesub-scanning direction by the page memory 76.

[0123] That is, the read image is once stored into the page memory 76 bywrite scanning operations W1, W2, . . . Wn repeated in the regulardirection X of the sub-scanning, as shown in FIG. 27. Further, the imagethus stored in the page memory 76 is read by the read scanningoperations R1, R2, . . . Rn repeated in the reverse direction X′ of thesub-scanning, as shown in FIG. 28.

[0124] The read image, which is a reversed image, is printed on acopying paper C through the photosensitive drum 20 by scanning on thephotosensitive drum 20 with the laser beam B emitted from the laser unit27 (step 310).

[0125] That is, the laser beam B modulated on the basis of the readimage is emitted from the laser unit 27. As shown in FIG. 29, this laserbeam B is swung in the axis direction of the photosensitive drum 20,thereby to repeat line scanning on the surface of the photosensitivedrum 20. By this repetition of line scanning and rotation of thephotosensitive drum 20, an electrostatic latent image is formed on thesurface of the photosensitive drum 20. This electrostatic latent imageis an image corresponding to reversal of the image of the character “A”on the original document D. This electrostatic latent image is developedto form a visual image which is transferred to a copying paper C.

[0126] Repetitions of line scanning with the laser beam B correspondrespectively to main scanning operations P1, P2, . . . Pn in onedirection Y on the copying paper C, as shown in FIG. 30. As the copyingpaper is fed, the main scanning operations P1, P2, . . . Pn shift in thedirection X (which is the regular direction of the sub-scanning)perpendicular to the one direction Y, i.e., in the direction from theleft end C1 to the right end C2 of the copying paper C.

[0127] Thus, the image of the original document D, which is notreversed, is printed on the copying paper C. The printed copying paper Cis fed to the sorter 44.

[0128] If there is any sheet of the original document D remaining on theautomatic document feeder 47 (NO in the step 308), the processes of thesteps 304, 305, 306, 309, and 310 are repeated. When no sheet of theoriginal document D remains on the automatic document feeder 47 (YES inthe step 308), the printing ends.

[0129] If a plurality of printed copying papers C are layered andstapled, the staple unit 46 operates to perform stapling S at a specificposition on each copying paper C, as shown in FIG. 30. The specificposition is a corner part existing between the right end C2 and thelower end C4 of each copying paper C and is situated at an upper leftposition where it is viewed with respect to the printed image taken as areference, like in the normal print mode and the mirror image print modein which printing is carried out with the original document D set on thedocument table 2, and also like in the mirror image print mode in whichprinting is carried out with the original document D set on theautomatic document feeder 47.

[0130] As described above, in the normal print mode according to thesheet-through read system, processing for reversing a read image by thepage memory is required. However, with respect to the mirror image printmode according to the document table read system and the mirror imageprint mode according to the sheet through read system, printing can beeasily completed without necessitating the reversal processing by thepage memory 76. Accordingly, the image processing can be simplified sothat the present invention is applicable to an image forming apparatusof a low cost type.

[0131] In addition, the position of the stapling S with respect to eachcopying paper C can be set in common to all modes in the cases of thenormal print mode and the mirror image print mode according to thedocument table read system, as well as both modes according to thesheet-through read system. Therefore, regardless of differences betweenthe read systems and between print modes, stapling S can be performedalways at a proper position in relation to an image to be printed, as areference.

[0132] Additional advantages and modifications will readily occur tothose skilled in the art. Therefore, the invention in its broaderaspects is not limited to the specific details and representativeembodiments shown and described herein. Accordingly, variousmodifications may be made without departing from the spirit or scope ofthe general inventive concept as defined by the appended claims andtheir equivalents.

What is claimed is:
 1. An image forming apparatus comprising: a documenttable on which an original document is set; read means for reading animage of the original document set on the document table, by opticalmain scanning on the original document set on the original table, in onedirection, and sub-scanning in which the mains scanning is shifted in adirection perpendicular to the one direction; a printer section forexecuting main scanning and sub-scanning in synchronization with themain scanning and the sub-scanning performed by the read means, therebyto print the image read by the read means, onto an image forming medium;and control means for setting the direction of the sub-scanning of theread means to a normal direction, in case of a normal print mode inwhich the image of the original document set on the document table isprinted on the image forming medium, with the image not reversed, andfor setting the direction of the sub-scanning to a direction opposite tothe normal direction, in case of a mirror image print mode in which theimage of the original document set on the original table is printed onthe image forming medium, with the image reversed.
 2. The apparatusaccording to claim 1, wherein the read means includes exposure means,which is provided to be capable of making reciprocal motion, forexposing the original document set on the document table, and imagesignal output means for receiving reflection light from the originaldocument, which is caused by exposure by the exposure means, forperforming main scanning on a light receiving area thereof, and forperforming sub-scanning in which the main scanning is repeated as theexposure means moves on a forward way of the reciprocal motion thereof,thereby to output an image signal corresponding to the image of theoriginal document.
 3. The apparatus according to claim 1, wherein theread means includes an exposure lamp for exposing the original documentset on the document table, a carriage for letting the exposure lamp makereciprocal motion along the document table, and a CCD for receivingreflection light from the original document, which is caused by exposureby the exposure lamp, for performing main scanning on a light receivingarea thereof, and for performing sub-scanning in which the main scanningis repeated as the exposure lamp moves on a forward way of thereciprocal motion, thereby to output an image signal corresponding tothe image of the original document.
 4. The apparatus according to claim1, wherein the printer section includes a photosensitive drum, a laserunit for performing main scanning on a surface of the photosensitivedrum with a laser beam, in one direction, and sub-scanning in which themain scanning is repeated in accordance with rotation of thephotosensitive drum, thereby to form an electrostatic latent imagecorresponding to the image read by the read means, on the surface of thephotosensitive drum, a developing device for developing theelectrostatic latent image formed on the surface of the photosensitivedrum, thereby to visualize the electrostatic latent image, and atransfer device for transferring a visualized image on the surface ofthe photosensitive drum, to the image forming medium.
 5. The apparatusaccording to claim 1, wherein the read means includes exposure means,which is provided to be capable of making reciprocal motion, forexposing the original document set on the document table, and imagesignal output means for receiving reflection light from the originaldocument, which is caused by exposure by the exposure means, forperforming main scanning on a light receiving area thereof, and forperforming sub-scanning in which the main scanning is repeated as theexposure means moves on a forward way of the reciprocal motion thereof,thereby to output an image signal corresponding to the image of theoriginal document, and the control means sets a direction of thereciprocal motion of the exposure means to a normal direction, in caseof a normal print mode, and switches the direction of the reciprocalmotion of the exposure means to a direction opposite to the normaldirection, in case of a mirror image print mode.
 6. The apparatusaccording to claim 1, wherein the read means includes an exposure lampfor exposing the original document set on the document table, a carriagefor letting the exposure lamp make reciprocal motion along the documenttable, and a CCD for receiving reflection light from the originaldocument, which is caused by exposure by the exposure lamp, forperforming main scanning on a light receiving area thereof, and forperforming sub-scanning in which the main scanning is repeated as theexposure lamp moves on a forward way of the reciprocal motion, therebyto output an image signal corresponding to the image of the originaldocument, and the control means sets a direction of the reciprocalmotion of the exposure lamp to a normal direction, in case of a normalprint mode, and switches the direction of the reciprocal motion of theexposure lamp to a direction opposite to the normal direction, in caseof a mirror image print mode.
 7. The apparatus according to claim 1,further comprising a staple unit for performing stapling at apredetermined position of the image forming medium on which the imagehas been printed by the printer section.
 8. An image forming apparatuscomprising: a document table on which an original document is set; adocument read window; a document feeder for feeding the originaldocument, which is set, onto the document read window and for lettingthe original document pass over the document read window; first readmeans for performing optical main scanning on the original document seton the document table, in one direction, and sub-scanning in which themain scanning is shifted in a direction perpendicular to the onedirection, thereby to read an image of the original document set on thedocument table; second read means for performing main scanning on theoriginal document, which passes through the document read window,through the document read window, and sub-scanning in which the mainscanning is repeated as the original document passes over the documentread window, thereby to read the image of the original document whichpasses over the document read window; a printer section for executingmain scanning and sub-scanning in synchronization with the main scanningand sub-scanning performed by the first and second read means, therebyto print an image, which is read by the first and second means, to animage forming medium; first control means for letting the first readmeans function to set a direction of the sub-scanning of the first readmeans to a normal direction, in case of a normal print mode in which theimage of the original document set on the document table is printed onthe image forming medium, with the image of the original document notreversed, and for letting the first read means function to switch thedirection of the sub-scanning of the first read means to a directionopposite to the normal direction, in case of a mirror image print modein which the image of the original document set on the document table isprinted on the image forming medium, with the image of the originaldocument reversed; and second control means for letting the second readmeans function in case of a mirror image print mode in which the imageof the original document set on the document feeder is printed on theimage forming medium, with the image of the original document reversed.9. The apparatus according to claim 8, wherein the first read meansincludes exposure means, which is provided to be capable of makingreciprocal motion, for exposing the original document set on thedocument table, and image signal output means for receiving reflectionlight from the original document, which is caused by exposure by theexposure means, for performing main scanning on a light receiving areathereof, and for performing sub-scanning in which the main scanning isrepeated as the exposure means moves on a forward way of the reciprocalmotion thereof, thereby to output an image signal corresponding to theimage of the original document.
 10. The apparatus according to claim 8,wherein the second read means includes exposure means for exposing theoriginal document which passes over the document read window, and imagesignal output means for receiving reflection light from the originaldocument, which is caused by exposure by the exposure means, forperforming main scanning on a light receiving area thereof, and forperforming sub-scanning in which the main scanning is repeated as theoriginal document passes over the document read window, thereby tooutput an image signal corresponding to the image of the originaldocument.
 11. The apparatus according to claim 8, wherein the first readmeans includes an exposure lamp for exposing the original document seton the document table, a carriage for letting the exposure lamp makereciprocal motion along the document table, and a CCD for receivingreflection light from the original document, which is caused by exposureby the exposure lamp, for performing main scanning on a light receivingarea thereof, and for performing sub-scanning in which the main scanningis repeated as the exposure lamp moves on a forward way of thereciprocal motion, thereby to output an image signal corresponding tothe image of the original document.
 12. The apparatus according to claim8, wherein the second read means includes an exposure lamp for exposingthe original document which passes over the document read window, and aCCD for receiving reflection light from the original document, which iscaused by exposure by the exposure lamp, for performing main scanning ona light receiving area thereof, and for performing sub-scanning in whichthe main scanning is repeated as the original document passes over thedocument read window, thereby to output an image signal corresponding tothe image of the original document.
 13. The apparatus according to claim8, wherein the printer section includes a photosensitive drum, a laserunit for performing main scanning on a surface of the photosensitivedrum with a laser beam, in one direction, and sub-scanning in which themain scanning is repeated in accordance with rotation of thephotosensitive drum, thereby to form an electrostatic latent imagecorresponding to the image read by the read means, on the surface of thephotosensitive drum, a developing device for developing theelectrostatic latent image formed on the surface of the photosensitivedrum, thereby to visualize the electrostatic latent image, and atransfer device for transferring a visualized image on the surface ofthe photosensitive drum, to the image forming medium.
 14. The apparatusaccording to claim 8, wherein the first read means includes exposuremeans, which is provided to be capable of making reciprocal motion, forexposing the original document set on the document table, and imagesignal output means for receiving reflection light from the originaldocument, which is caused by exposure by the exposure means, forperforming main scanning on a light receiving area thereof, and forperforming sub-scanning in which the main scanning is repeated as theexposure means moves on a forward way of the reciprocal motion thereof,thereby to output an image signal corresponding to the image of theoriginal document, and the first control means sets a direction of thereciprocal motion of the exposure means to a normal direction, in caseof a normal print mode, and switches the direction of the reciprocalmotion of the exposure means to a direction opposite to the normaldirection, in case of a mirror image print mode.
 15. The apparatusaccording to claim 8, wherein the first read means includes an exposurelamp for exposing the original document set on the document table, acarriage for letting the exposure lamp make reciprocal motion along thedocument table, and a CCD for receiving reflection light from theoriginal document, which is caused by exposure by the exposure lamp, forperforming main scanning on a light receiving area thereof, and forperforming sub-scanning in which the main scanning is repeated as theexposure lamp moves on a forward way of the reciprocal motion, therebyto output an image signal corresponding to the image of the originaldocument, and the first control means sets a direction of the reciprocalmotion of the exposure lamp to a normal direction, in case of a normalprint mode, and switches the direction of the reciprocal motion of theexposure lamp to a direction opposite to the normal direction, in caseof a mirror image print mode.
 16. The apparatus according to claim 8,further comprising a staple unit for performing stapling at a specificposition on the image forming medium on which the image has been printedby the printed section.